Guangdong, which borders Hong Kong, recorded 20 new confirmed cases, all contracted locally, in the 24 hours through to midnight yesterday.
Guangdong’s numbers are low compared with many places in the world, but the rise has rattled Chinese leaders who thought they had the disease under control.
People leaving Guangdong by plane, train, bus or private car after 10pm today must present results of a nucleic acid test within the past 72 hours, the provincial government announced. It said testing stations for truck drivers would be set up on major roads.
The government of the provincial capital, Guangzhou, a business centre of 15 million people, ordered mass testing after locally acquired infections were found beginning 21 May. The government said 700,000 people had been tested through last Wednesday.
China had relaxed most restrictions on domestic travel after the ruling Communist Party declared the virus under control last March. Travellers arriving from abroad still must be tested.
On Saturday, residents of one Guangzhou neighbourhood were ordered to stay at home for door-to-door testing. In some areas, outdoor markets and child care facilities were closed and in-person grade school classes and indoor restaurant dining canceled.
China reports a handful of new cases every day but says almost all are believed to be people who were infected abroad. The mainland’s official death toll stands at 4,636 out of 91,099 confirmed cases.